Converting understairs


Converting understairs

Staircases take up a surprising amount of space. The housebuilder’s way to put some of this to use is to enclose the understairs area to form a cupboard. But all too often the cupboard under the stairs is an awkward shape and difficult to get into, making it of limited practical value. Knocking out the cupboard may allow a forgotten area to become part of the living space.

How much space there is to be gained, and how easy the job will be, depends on the type of stair layout and support. Timber stairs usually have at least one load-bearing timber post – called a newel – running up from the floor to the stair. This cannot be removed without providing alternative support.

Staircase support

There are several common arrangements for supporting a staircase. The simplest is the straight-run stair, which has the most easily-used under- stairs space. The stair is supported by full newels at each end of the outer string, leaving a large, unobstructed triangular space underneath. The cupboard panelling will probably have extra studs to support it, particularly if the cupboard door is not hung from the newel, but these extra timbers can usually be removed without problem.

The straight-run staircase is also used when stairs are fitted into a narrow corridor, with both strings supported by the walls. Here, although the understairs space is the same, access is in the room behind the stair, with a cupboard door opening under the landing. With this type of space, opening the cupboard out to the side is rarely practical as in most cases both walls are loadbearing; as is the lintel over the door which supports the landing.

Quarter-turn stairs normally have a newel at the turn, supporting the landing and stairs. Where a cupboard is fitted, it will probably extend past this load-bearing timber to the wall under the landing. There is a variation in this type of stair, where the landing is supported on bearers set into the wall and the stairs are carried by the landing. If a cupboard has been added there may well be what appears to be a newel. However, it will not extend to the handrail or be fully jointed to the floor or string, and the bearers for the landing should be clearly visible from below. Where the newel is load- bearing, it must be left in place. This is a further restriction to the under- stairs space, which is of limited height.

Half-turn stairs are of similar construction. In open-well stairs, the second quarter landing may have a full newel, but it is often supported onbearers. A typical arrangement here has a low cupboard under the first flight, while the much taller space under the second flight and quarter landing forms a second cupboard, or sometimes a WC. Where the second quarter landing is supported on bearers, either or both of these areas can easily be opened up. But in some cases, the wall beneath the second flight is load-bearing, and cannot be removed without adding a newel or bearers to take its place.

Dog-leg stairs are often used to achieve a steep rise in a small space. To do this, the stair doubles back on itself with a second string fitted directly over the first. With these stairs, both strings and the half-landing are supported on a single, central newel. The top and bottom of the stairs have additional newels.


In spite of the fact that the space beneath is awkward and cramped, a cupboard is sometimes built under the upper flight. A further half newel is often added to support its panelling and door.

With any type of stair, the design may vary in detail, and there can be timbers whose purpose is not clear. A load-bearing newel will be fully fixed and jointed to the string or landing (often with a bolt and mortice). It will also be fixed and jointed to the joists or set into a solid floor. Most run to the handrail as well, although this is not a completely reliable guide. It is usually a heavy timber, around 100mm square, although it may be turned on some portions of its length.


The common causes of creaking joints. Wide staircases —more than stairs are loose or missing glue 900mm across -may creak because blocks, loose wedges or defective the centre is not well supported.

Removing a newel

When a staircase is supported by a newel it is possible to remove the newel and provide staircase support by some other means. But this structural conversion isn’t nearly as easy as it might appear. It’s a lot easier and cheaper to leave the newel in position and design the space conversion around this timber.

If you do want to remove a newel you’ll have to get professional advice and the alteration will require Building Regulations approval.

Removing the cupboard

Once you have found out which timbers, if any, can safely be removed, knocking out the panels of the cupboard is a simple enough task. You may find a partition closing off the

Glue blocks There should be at least three beneath each tread. Check that these are in position and replace any that are loose. If any blocks are actually missing, glue on new triangular blocks of softwood the same size as the existing.

Wedges Wedges can work loose through shrinkage, remove any that are loose, coat with glue and rewedge. If that isn’t firm enough, it may be necessary to cut new wedges and bottom corner of the stair. Since this triangular space is difficult to clean and to use, it’s often better to leave it enclosed.

If the underside of the stair is open, fit a flush panel to the strings and bearers. It is sensible to use screws to fix this so that access is easier if it ever becomes necessary to repair the stairs. If the stairs are already creaking or knock them in place

Defective joints If the joint between a tread and riser has drawn apart, screws up through the underside of the tread into the riser will pull the joint together. Be careful to position the screw in the centre of the riser or you’ll risk splitting the wood. Use three screws evenly spaced across the stair width. Wax the screws before driving home and tighten them gradually in turn.

Showing signs of wear it makes sense to repair them first.

The service fittings – the gas and electricity meters, fuseboard or consumer unit – are often installed in the cupboard under the stairs. If these are in the way, you can pay for the appropriate service authority to reposition them – or for neatness you can box them in with an access panel.


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